Phenol, reaction with dimethyl sulfide

An alternative method of synthesizing the pyrazine compounds was described by Ghosh et al, and the synthesis is shown is Scheme 32 [78]. Reaction of a 1,2-dione (124) with a 1,2-diamine (125) to form an imine intermediate followed by spontaneous oxidation of the dihydropyrazine intermediate, formed the protected pyrazine compound 126. The free phenol 127 was obtained by removal of the methyl-protecting groups with a boron trifluoride-dimethyl sulfide complex. Similar compounds were prepared via the same method by Simoni et al. [79]. 

Chlorination of Aromatic Compounds. NCS has also been used for the chlorination of pyrroles and indoles however, the reaction is less straightforward than when NBS and N-Iodosuccinimide are used. In the chlorination of 1-methylpyrrole, it has been demonstrated that basic conditions (NaHCOs, CHCI3) lead to the formation of 1-methyl-2-succinimidylpyrrole (eq 11). In the presence of catalytic amounts of perchloric acid, thiophenes and other electron-rich aromatic compounds have been chlorinated with NCS. (N-Chlorosuccinimide-Dimethyl Sulfide is used for the selective -substitution of phenols.)... 

Dialkyl derivatives of aniline, diphenylamine, and carbazole, when melted with benzotrichloride and fused zinc chloride, yield triphenylmethane dyes of the malachite green type. Phenols, diphenyl sulfide, and indole react as well, but the dyes obtained are red. This test can be completed by identifying the triphenylmethane dye formed by paper chromatography (22) to differentiate, for example, dimethyl- and diethylaniline. A similar reaction results from melting the sample with oxalic acid. This reaction leads to the formation of blue dyes, characteristic of the derivatives of diphenylamine and carbazole (23). 

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